Pirn barrel and method of forming same



Sept. 19, 1961 c. K. DUNLAP ETAL 3,000,590

PIRN BARREL AND METHOD OF FORMING SAME 2 Sheets-Sheet 1 Filed June 25, 1956 46 QJL'MFE.

@IIIIIIIII I INVENTORS CHA RLES A. DUNLAP WILLIAM B. BROADBENTfr BY JOSEPH x. ravwn A TTORNEVJ p 1961 c. K. DUN LAP ET AL I 3,000,590

PIRN BARREL AND METHOD OF FORMING SAME Filed June 25, 1956 2 Sheets-Sheet 2 Ii 9*. 7 w w Z2 ll Fig.5 I L Fig 6 WILLIAM B. BROMJBENT 5 BY JOSEPH K. TAYLOR ATTORNEYJ United States atent O PIRN BARREL AND METHOD OF FORMING SAME Charles K. Dunlap, William B. Broadbent, and Joseph K. Taylor, Hartsville, S.C., assignors to Sonoco Products Company, a corporation of South Carolina Filed June 25, 1956, Ser. No. 593,551 Claims. (Cl. 242-11831) This invention relates to pirns of the type commonly used to carry textile yarn packages for certain purposes, and more particularly to an improved pirn barrel structure.

A principal use for pirns is in the shipment of synthetic yarns by the yarn manufacturer to customers. In handling a shipping size yarn package it is usual to employ an inner metal reinforcing. tube in the pirn structure to withstand the considerable compressive stresses that accumulate at the yarn package core due to the elastic properties of most synthetic yarns which are brought into play as the yarn is wound under tension to form a package.

As metal does not provide a suitable yarn winding surface, pirn structures incorporating a reinforcing tube have also characteristically included a covering on the reinforcing tube to form a pirn barrel presenting a winding surface on which the yarn windings may be Wound and withdrawn satisfactorily. It has been found that the most practical pirn barrel covering for this purpose is a paper tube structure slipped over the inner reinforcing tube and secured in place thereon. A paper tube structure is not only a relatively inexpensive covering means but can also be adapted to excellent advantage in forming a winding surface of the particular characteristics needed in a given instance.

However, the matter of securing a paper tube covering in place on a reinforcing tube has proved troublesome because of the necessity for replacing the covering from time to time as it becomes worn, the inner reinforcing structure naturally being more durable and accordingly being reusable many times upon recovering. It has been common prior practice to use crimped ferrule type end fittings for assembling the pirn structure so as to hold the barrel covering in place, but this arrangement has involved the substantial disadvantage of requiring a special reworking operation by the pirn manufacturer to remove and reassemble these end fittings whenever the barrel covering needed replacement.

According to the present invention a paper barrel covering for a reinforced pirn structure is provided that can be installed to remain in place effectively on a reinforcing tube simply by pressing it over the tube in covering relation, so that no additional securing means of any sort is needed and the barrel covering may accordingly be removed readily for replacement whenever necessary as a normal incident of handling the pirns during the regular course of use by the yarn manufacturer, so as to eliminate entirely any special reworking operation such as has heretofore usually been required. I

The present invention is described in further detail below in connection with the accompanying drawings, in which: I

FIG. 1 is a vertical section of a pirn incorporating the barrel structure of the present invention;

FIG. 2 is an enlarged fragmentary detail illustrating the relative arrangement of the pirn reinforcing tube and barrel covering as the latter-is installed in place,

FIG. 3 is a'sectional detail of a modified form of top end fitting that may be used in place of the one" shown in FIG. 1;

FIG. 4 is a further sectional detail illustrating another modification of the top end fitting;

FIG. 5 is a vertical section illustrating the paper tube ice structure used as a preform for the barrel covering provided according to the present invention;

FIG. 6 is a sectional detail showing the preform of FIG. 5 after one end thereof has been curled inwardly according to the present invention;

FIG. 7 is a sectional detail illustrating the molding step employed in forming the barrel covering from the preform illustrated in FIGS. 5 and 6;

FIG. 8 is an enlarged detail of the tip of the core pin shown in FIG. 7, with the molded barrel covering illustrated in section in relation thereto;

FIG. 9 is a fragmentary detail illustrating a modified form of the core pin tip illustrated in FIG. 8; and

FIG. 10 is a further fragmentary detail illustrating another modification of the core pin tip.

Referring now in detail to the drawings, and more particularly at first to FIG. 1, the pirn structure illustrated comprises a barrel covering 10 installed on a reinforcing tube 12 with a drive end fitting 14 secured within the lower end of the reinforcing tube 12, an auxiliary reinforcing collar 16 and a spindle bushing 18 fixed in spaced relation within the reinforcing tube 12, and a top end fitting 20 installed at the upper end of the pirn structure as is described more in detail further below.

As previously mentioned, the reinforcing tube 12 is formed of metal to provide adequate strength in the pirn structure, a seamless steel tube being commonly used. Also, the drive end fitting 14, auxiliary reinforcing collar 16 and spindle bushing 18 are likewise normally formed of metal.

The barrel covering 10, however, is a specially formed paper tube structure provided according to the present invention for a push fit on the reinforcing tube 12 except adjacent an inturned end portion 22 thereof which is shaped for bottoming disposition over the adjacent end of the reinforcing tube 12 and at which the inner diameter of the barrel covering 10 is reduced, as illustrated at 24 in FIG. 2, for gripping the reinforcing tube 12 upon bottoming of the end portion-22 thereon, so as to retain the barrel covering 10 in place effectively during use of the pirn structure while still allowing it to be removed readily from the reinforcing tube 12 for replacement.

The manner in which this barrel covering 10 is formed according to the present invention is illustrated in FIGS. 5 through 10 of the drawings. FIG. 5 illustrates a length of paper tubing 10' such as is used as a preform for the barrel covering 10. This preform 10' comprises a laminated paper tube structure suitably formed by convolutely winding a sheet of kraft paper or the like with an adhesive applied to bond the windings and thereby secure the wound tube structure. The preform 10 is also impregnated with a polymerizable resin, such as a phenolic resin, which may be applied either to the paper sheet before winding or to the wound tube, for a purpose that is described fu-rther'below.

One end of the preform 10' is then curled inwardly as illustrated at 22' in FIG. 6. The preform 10 is originally formed as shown in FIG. 5 with an inner diameter proportioned for a push fit with the reinforcing tube 12 on which it is to be installed. This inner diameter is maintained while the-inturned end portion 22' is formed as shown in FIG. 6, and this end portion 22 is shaped at this stage for bottoming disposition over an adjacent end of the reinforcing tube 12.

The paper tube preform structure 10 with the inturned end portion 22 is then folded to form the barrel covering 10 by means of a mold 26 and core pin 28 such as is illustrated in FIG. 7, the mold 26 having an entrance taper 30 to provideforradially compressing the wall of thepreform 10' as' it is inserted in the mold 26 on the corepin 28. The core pin 28 is proportioned generally as a counterpart of the reinforcing tube 12, on which the barrel covering is later to be installed, so that the preform 16' can be pushed thereon; the base end of the core pin 28 being fitted with a sleeve 32 to provide a bearing shoulder for the lower end of the preform 10' (and of the resulting barrel covering 10), and carrying a head portion 34 of special form to support the inturned end 22' of the preform 10' during the molding operation so as to have the inturned end portion 22 properly formed in the finished barrel covering 10 with the reduced inner barrel wall diameter 24 provided thereat. The arrangement of the core pin head portion 34 for this purpose is illustrated in FIG. 8, in which the head'portion 34 is shown relieved at its tip with a shouldered configuration, as indicated by the reference numeral 36, which allows the formation of the reduced inner wall portion 24 in the barrel covering 10 during molding.

In a typical case, the preform 10' is originally formed with a wall thickness of about .075 inch. The mold 26 is proportioned so that this wall thickness is reduced by radial compression during the molding operation to .050 inch, except at the relieved portion 36 on the core pin head 34, where the radial compression results in reducing the diameter of the inner barrel wall to fit the relief at 36 which may be of the order of .010 inch on the diameter and about to inch in length.

The result of the radial compression effected during the molding operation is to form a relatively dense wall in the barrel covering 10 that presents a hard, smooth surface providing an excellent yarn winding surface and having exceptionally good scuif resistant properties. At the same time, it should be noted that the formation of the reduced inner wall portion 24 in the barrel covering 10 during the molding operation results in rendering the wall less dense at this point and relatively resilient so as to adapt the inner wall portion 24 particularly for exerting a gripping action on the reinforcing tube 12 when the barrel covering 10 is installed in place. Also, it should be noted that the molding operation is carried out according to the present invention under the influence of heat, the mold 26 being suitably jacketed (not shown) and supplied with process steam to maintain a mold temperature of the order of about 260 F. to 400 P. so as to polymerize and set the previously mentioned resin impregnant in the preform 10 as the barrel covering 10 is formed therefrom, and thereby set the structure of the barrel covering 10 with the above noted relatively dense wall except for the inner wall portion 24 at which the wall is rendered less dense and relatively resilient.

The completed barrel covering 10 may then be installed on the reinforcing tube 12 simply by pressing it over the tube 12 in covering relation with the inturned end portion 22 bottomed at the adjacent end of the tube 12. Because the barrel covering 10 is formed for the most part of its length with an inner diameter proportioned for a push fit on the reinforcing tube 12, it may in fact be slid by hand onto the reinforcing tube 12 until the inner wall portion 24 of reduced diameter is reached by the adjacent end of the tube 12. At this point a substantially increased pressure is needed to force the barrel covering 10 home to a position at which the inturned end 22 is fully bottomed on the reinforcing tube 12. As the barrel covering 10 is pressed home to complete this bottoming, the inner wall portion 24 is forced over the adjacent end portion of the reinforcing tube 12 to apply a gripping action thereon and secure the barrelcovering 10 in place effectively for use, while at the same time leavcause the ends of the reinforcing tube 12 are normally chamfered. However, comparable results might be obtained, if desired in particular instances, by forming the core tip head 34 with a radial tip reduction as illustrated at 38 in FIG. 9, or with a tapered reduction as illustrated at 40 in FIG. 10.

In order to maintain the full advantage of the arrangement of the barrel covering 10 for easy installation on and removal from the reinforcing tube 12, the top end fitting provided according to the present invention is also arranged for installation and removal at the inturned barrel covering end portion 22 just as easily. For this purpose, the top end fitting 20 is shaped with a peripheral groove 42 formed for seating interiorly at the inturned barrel covering end 22 and is otherwise shaped with a rounded peripheral edge portion below the" groove 42 so that it may be pressed through this inturned end 22 to ing the barrel covering 10 easily removable upon simply exerting suificient pressure in the opposite direction to break the gripping action of this inner wall portion 24 so that the barrel covering 10 may be slid therefrom just as easily as it was installed.

The shouldered configuration of the reduced diameter inner wall portion 24 is preferred because it applies a more or less uniform gripping action over its entire length, and this configuration can be used readily beseat the peripheral groove 42 thereat. Because the structure of the inturned barrel covering end 22 renders it in herently resilient to some extent at its inner diameter, the top end fitting 20 can be readily arranged for installation and removal by hand, while remaining securely in place during use. The top end fitting 20 also serves the useful purpose of eliminating any tendency of the inturned barrel covering end 22 to open up or partially uncurl as might sometimes otherwise occur during use of the pirn structure in moist atmospheres. In addition, the top end fitting 20 may be readily formed with a seat at 44 for an identification disc.

FIG. 3 of the drawing illustrates a modified form of top end fitting 46, which is formed substantially like the previously described top end fitting 20 except that it is shaped above the peripheral groove 48 therein with a top portion 50 of enlarged diameter proportioned to overlie substantially the entire top of the inturned barrel covering end 22 and thereby allow the pirns on which it is used to be stacked during shipment while fully protecting the end 22 against scuffing. Both of the top end fittings 20 and 46 shown in FIGS. 1 and 3 are adapted particularly to be formed of molded plastic. FIG. 4 shows a still further modified top end fitting 52 arranged to be formed of metal, and in which a peripheral groove 54 is formed in a slotted skirt portion 56 that allows installation and removal of this top end fitting 52 in the nature of a collet.

The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise except as defined in the appended claims.

We claim:

1. In a pirn for carrying the windings of a textile yarn package, the combination with an inner metal reinforcing tube of a covering therefor comprising a laminated and resin impregnated paper tube structure characterized by a relatively dense, radially compressed wall, said paper tube structure being of uniform exterior diameter and being proportioned in diameter interiorly for a push fit on said reinforcing tube except at an inturned end portion of said paper tube that is shaped for bottoming disposition over an adjacent end of said reinforcing tube, said inturned end port-ion being less compressed than the rest of the tube structure and the inner diameter of said paper tube at said inturned end portion is reduced for gripping said reinforcing tube upon bottoming of said end portion thereon, said reduced inner paper tube diameter rendering the paper tube wall thereat less dense and thereby imparting a relative resilience thereto for said gripping action.

2. The method of forming a covering on an inner metal reinforcing tube in a pirn for carrying the windings of a textile yarn package, which method comprises forming a laminated and resin impregnated paper tube structure with an inner diameter proportioned for a push fit on said reinforcing tube, inturning one end of said paper tube structure for bottoming disposition over an end of said reinforcing tube, radially compressing the wall of said paper tube structure while maintaining said inner diameter except adjacent said inturned end, reducing said inner diameter adjacent said inturned end during said radial compression, and carrying said radial compression out under the influence of heat and thereby setting said resin impregnated paper tube structure with a relatively dense wall except at the wall portion having said reduced inner diameter at which the wall is rendered less dense and relatively resilient.

3. In a pirn for carrying the windings of a textile yarn package, the combination with an inner metal reinforcing tube of an outer paper barrel and a top end fitting, said barrel being proportioned in diameter for a push fit on said reinforcing tube and having an inturned top end portion shaped for bottoming disposition over the adjacent end of said reinforcing tube, and said top end fitting having a peripheral groove formed for seating interiorly at said inturned barrel end and being otherwise formed with a rounded peripheral edge portion below said groove for pressing through said inturned end to seat said peripheral groove at the inturned portion with said rounded peripheral edge portion seated over the interior end of said inturned end.

4. A barrel and a top end fitting therefor adapted for use on textile yarn pirns of the type incorporating an inner metal reinforcing tube, said barrel being formed of a multiply, laminated, paper tube proportioned in diameter for a push fit on said reinforcing tube and having an inwardly curled top end shaped for disposition over the adjacent end of said reinforcing tube, and said top end fitting having a peripheral groove therein that is rounded in cross section for seating interiorly at said curled top end of the barrel and being otherwise formed with a rounded peripheral edge portion below said groove 6 for pressing through said curled top end to seat said peripheral groove removably at said inwardly curled top end with said rounded peripheral edge portion seated over the interior end of said curled top end.

5. A top end fitting for an outer paper pirn barrel formed for use with an inner metal reinforcing tube and having an inwardly curled top end shaped for disposition over an adjacent end of said reinforcing tube, said top end fitting having a central opening therethrough and a peripheral groove therein that is rounded in cross section for seating interiorly at said curled top end of said barrel and being otherwise formed with a rounded peripheral edge portion below said groove for pressing through said curled top end to seat said peripheral groove removably at said inwardly curled top end with said rounded pe-. ripheral edge portion seated over the interior end of said curled top end and means forming a seat for an identification disc within said opening.

References Cited in the tile of this patent UNITED STATES PATENTS 192,493 Draper June 26, 1877 398,670 Stone et al. Feb. 26, 1889 487,434 Steen Dec. 6, 1892 1,085,100 Baekeland Jan. 27, 1914 1,996,741 Benge Apr. 9, 1935 2,101,324 Warner Dec. 7, 1937 2,320,965 Cotchett et al. June 1, 1943 2,377,920 Atwood June 12, 1945 2,678,781 Dunlap May 18, 1954 2,679,988 Morgan June 1, 1954 FOREIGN PATENTS 518,185 Italy Mar. 4, 19 

